3.3 Compiling For Multiple Architectures

You can compile the package for more than one kind of computer at the
same time, by placing the object files for each architecture in their
own directory. To do this, you can use GNU make.
cd to the directory where you want the object files and
executables to go and run the configure script.
configure automatically checks for the source code in the
directory that configure is in and in ... This is
known as a VPATH build.

With a non-GNU make,
it is safer to compile the package for one
architecture at a time in the source code directory. After you have
installed the package for one architecture, use ‘make distclean’
before reconfiguring for another architecture.

On MacOS X 10.5 and later systems, you can create libraries and
executables that work on multiple system types—known as fat or
universal binaries—by specifying multiple -arch options
to the compiler but only a single -arch option to the
preprocessor. Like this: